Ions and Precipitation Charging in Warm and Cold Clouds as Simulated in One-Dimensional Time-Dependent Models

Abstract

One-dimensional time-dependent models of warm and cold clouds were constructed to test the electrical and precipitation development in the presence of a variety of charge separation mechanisms. The, models simulate charging by ion diffusion, the Wilson effect (ion conduction), polarization induction, the Workman-Reynolds effect and the thermoelectric effect. It was found that charging by ion processes does not significantly contribute to the electrical development of either warm (shallow or deep) of cold clouds. In cold continental clouds, without ice multiplication processes, charging due to ice-ice collisions did not significantly contribute to the electrical buildup because of the low concentrations of ice particles and their low electrical conductivities at low temperatures. The most significant charging resulted from collisions of ice particles and water droplets. These collisions produced strong charging by both the inductive and non-inductive processes. It also was found that when both polarization and the Workman-Reynolds effect operate together, strong Acids develop. The resulting locations of the main charge centers and the corresponding electric fields in the model are in agreement with many recent observations, pointing to the presence of a negative charge center around the ?10°C level. The effect of corona discharge from the ground on the ion concentration and ion charging near and below cloud base, and on the electrical conductivities within the cloud, also were found to agree well with many recent observations.